I am not sure if this is the service I am thinking of, but try playing around with the junctions on the far side of your next way. point.
There's quite a few switches in that yard, if I have to try out all the different combinations, I'll be busy for a while. So more specific hints would be appreciated.
I think you´ll find the correct sequence in this thread: Signaller Problem On First Service With Class 37 6h02 St Austell - Penzance Class 37 Check Switches